This invention relates to reducing the consumption of electrical power necessary for the production of light and, more specifically, to a circuit module for converting AC current to a train of DC pulses flowing to a light-emitting load resistor.
In view of the ever rising cost of electrical power, there exists a commensurately growing need to find additional novel means for achieving energy savings by increased efficiency.
Various improvements have therefore been introduced since the advent of Edison's light bulb such as, to mention a few, using a tungsten filament and metal halide as incandescent material, coating the inner surface of the glass bulb or mounting the bulbs on specular reflectors. In addition, a power saving has been provided by the wide spread, if not universally desirable replacement of incandescent light sources by fluorescent lamps. The general objective has been directed to increasing the luminosity per unit electrical power consumed by improving the light-emitting load of a given circuit.
The purpose of my invention is therefore to provide a new power supply to reduce the consumption of electricity, by, more particularly, a low cost, small size and easily produced converting circuit for altering the conventional sinusoidal AC waveform into direct current voltages. The network according to my present invention generates a train of pulse waves of extremely narrow pulse width. These pulses are amplified and directed into a fast switching power transistor. When the power transistor conducts the pulse train, current flows through the load for a time interval equal to the pulse width which may be measured in nanoseconds or microseconds. Since the useful energy is expended mainly during the pulse width but not during the resting period between pulses, which is relatively much larger than the pulse width, yet too short to be perceptible to the human eye, considerable energy can be saved while nevertheless maintaining brightness of illumination. In other words, the light-producing ultra short DC pulses are selected sufficiently close in sequence (say 4,000 pulses per second) to prevent the human eye because of its natural retentivity, to discern the intervening resting or nonpulsed periods as shadows. As is well-known in the lighting art, fluorescent light is perceived continuous at 60 cycles AC per second, which is above the time-resolving ability of the eye or critical fusion frequency (CFF). Another- benefit on my present invention is to increase the longevity of incandescent load resistor elements.
Preliminary aspects of my invention were disclosed on Nov. 27, 1989 to the United States Patent Office and received the receipt No. 240124.